Introduction The ELK Stack is made of three open-source products: 1) Elasticsearch, 2) Logstash, and 3) Kibana. Elasticsearch: It is a NoSQL database which is based on the open-source search engine called Lucene. So Elasticsearch is a search and analytics engine. Logstash: It is a data processing pipeline tool which accepts inputs from (multiple) sources,…

Here in this tutorial I will tell you what are Dynamic Tests and @TestFactory in Junit 5 and how to create @TestFactory in Junit 5. Test cases, annotated with @Test, are static in the sense that they are fully specified at compile time, and their behavior cannot be changed by anything happening at runtime. In…

Introduction Here in this tutorial I will show you an example on how to test private methods using Junit framework. I am using Junit 5 framework to test the private method. Using Mockito framework you won’t be able to test private methods, but using PowerMock core API you will be able to test the private…

In this example I am going to tell you how to map composite primary key to entity class in your JPA Hibernate entity class. Composite primary key is a combination of two or more columns made together as a primary key. Therefore the combination of column values will be as a unique instead of having…

In this example I am going to show you how to find all paths from root to leaf nodes in binary tree. So I am going to find each path from root to leaf node using Java program. A binary tree is a non-linear data structure type tree with at most two children for each…

Here I am going to show you how to find common, uncommon, unique elements in two Lists or ArrayLists using Java program. In this program I will show you how to find common, uncommon, unique string elements as well as object elements in two ArrayLists. For identifying the unique string elements is very straight forward…

Introduction In this tutorial I am going to show you how to create a custom immutable class in Java programming language. Immutable objects are those objects whose states cannot be changed. For example, you can change the state of an object by changing its attribute’s or field’s value. String is an example of the immutable…

I am going to discuss here CompletableFuture vs Parallel Stream in Java programming language. CompletableFuture extends Future with added advantage to allow the tasks finish in an ad hoc manner. In Parallel Stream task is divided into sub-tasks and run on separate threads to be completed faster. Both CompletableFuture and Parallel Stream were added in…

Here in this tutorial I am going to tell you how to configure Persistence Unit for JPA (Java Persistence API). Here I am going to show you both XML and Java based configurations for persistence unit in JPA. This is a pure Java application and I am not using Spring framework for this example. A…

In this example I am going to show you how to check if an input date is past date or today’s date or future date. I am using Java version 12 and for this example you should use at least Java version 8. Java 8 or higher version provides thread safe version of date time…

Here I am going to show you how to mask a field or an attribute in Java programming language. This kind of situation occurs when you are dealing with mainly debit or credit cards. So you have a POJO or model class for your card (debit or credit) but for security reason you do not…

In this example I am going to show you how to verify a method has been executed at least. Why do you need to verify method execution? Consider the void method, in your Java class, which you want to perform Junit test case on it and you don’t have any way to tell whether your…